Pneumatic tire.



Patented Oct 7, 1902. F. MITCHELL.

PNEUMATIC TIRE.

(Application filed July 8, 1902.)

2 SheetsSheet I. 7

(No Model.)

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Patented Oct. 7, 1902..

2 Sheets-Sheet 2.

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STATES ATENT Orricn.

FRANK IW'IITOIIELL, OF LONDON, ENGLAND.

ensure/arse rise.

SPECIFICATION forming part of Letters Patent No. 710,793, dated October7, 1902.

Application filed July 8, 1902. Serial No- 114,752. (No model.)

T o a, whrmt it may concern:

Be itknown that I, FRANK MITCHELL, a subject of the King of GreatBritain, residing at London, England, have invented certain new anduseful Improvements in and Relating to Pneumatic Tires for Cycles,Motor-Cars, and other Vehicles, of which the following is a full, clear,and exact description.

The invention relates to that class of pneumatic tire in which a numberof small airtight chambers are employed to fill the whole internalspace.

The object of the present invention is to provide means whereby thenecessary pressure may be obtained in the said small airtight chambersand whereby they may more easily fill up the space caused by one or moreof said air-tight chambers becoming punctured, thus equalizing theinternal pressure of the tire at all points.

The invention further relates to means whereby I am enabled to placesuch a tire more easily on the wheel.

The invention is illustrated in the accompanying drawings, in whichFigure 1 is an external viewof an air-chamber made entirely ofindia-rubber, such as I propose to employin the manufacture of pneumatictires. Fig. 2 is an external view of a modified form of said chamber inwhich a restraining-cover is placed around the central portion thereof.Fig. 3 is a sectional view of an air-tight chamber, showing one methodof producing the requisite pressure in air-chambers of the type shown inFig. 1. Fig. 4 is a sectional view of an air-tight chamber, show ing amethod of producing the requisite pressure in air-chambers of the typeshown in Fig. 2. Fig. 5 is a longitudinal section of part of a tireconstructed according to one form of my invention, and Fig. 6 is acrosssection of the same. Fig. Tis a cross-section of a similar tirefitted with a cover having endless wires, showing a special form of rimby means of which I am enabled more easily to fit the tire to the rim.Fig. 8 shows a method of locking the ends of the removable side. Fig. 9is a sectional View of a tire constructed with my special air-chambersarranged inside an ordinary inflatable air-tube. Fig. 10 shows theinvention applied to what is usually called a single-tube tire, or, morecorrectly speaking, to a tire having a closed tube as the outer cover.Fig. 11 shows a method of retaining the requisite air-pressu re in atire when one or more of the air-chambers have become deflated.

The air-chambers a are made of india-rubber, preferably of cylindricalform, having hemispherical ends. In Fig. l I have shown an air-chambermade entirely of india-rubber, which is closed at atmospheric pressureor slightly above the same. It is preferably made of thin material, sothat when reduced in sizeby external pressure there shall be no unduelumps. It may be made of such a size that before any excess ofpress'ureis placed therein it is the right diameter to fill the canvas bag inwhich it is to be placed. It is slightly expanded before closing, andwhen reduced in size, as hereinafter described, it will come back to itsoriginal dimensions. In Fig. 2 I have shown a similar chamber a,provided with a restraining-cover 1) around the central portion thereof.This cover is made just to fit snugly the interior of the canvas baginto which it is to be placed.

In Fig. 3 I show a method of getting airchambers a. of the type shown inFig. 1 into a bag of canvas or other suitable material under thepressure required for running purposes. The metal chamber cis providedwith caps c and flanges 0 which latter are connected by nuts and bolts 0for the purpose hereinafter explained. The chamber 0 is also providedwith an airpump d. The airchambers a are placed in a bag e, of suitablethin material, closed at both'ends. A tube f of stronger material issupported in the lower part of the chamber 0. In the drawings it isrepresented as hanging by tapes f, which are attached to the chamber 0by passing into the joint between the upper and lower parts thereof. Thebag 6, containing the chambers a, has a weight 6 attached thereto andrests on the top of the tube-f, with theweight e just inside the top ofthe tube f. The chamber c is closed air-tight, and pressure is producedtherein by means of the air-pump d.

hen sufficient pressure has been produced,

it will cause the air-chambers ato be reduced in size and will compressthe air contained therein to the same pressure as that in the metalchamber a. The weight 6' will then draw the bag 6, containing thechambers a, into the tube f. The air is then allowed to escape from thechamber a, and this latter is taken apart, when it will be found thatthe bag e will be located in the tube f, the bag 6 and tube f being thesame length, and the air-chambers a, being reduced in diameter, willretain the air contained therein under the necessary pressure. The tubefis then removed and is ready to be inserted into an outer cover.

In Fig. 4 I show a similar chamber a to that previously described,except that it is provided with means 0 for closing the upper part ofthe tube f, already closed at the bottom, when the chambers a have beeninserted therein under pressure. In this case I employ only one tube,hereinafter called the bagf, supported by tapesf from the up per part ofthe chamber 0. The air-chambers a, being restrained in diameter by thecovers a, will slip easily into the bag f, and a weight 9 is preferablyplaced on top of the chambers a. The chamber 0 is closed andair-pressure is applied, causing the hemispherical ends of the chambersato become flat, thus reducing their length and increasing the pressuretherein. When a weight e is employed, it assists in causing the chambersa to fall to the bottom of the bag f. When sufficient pressure has beenproduced in the chamber 0 and all the air-chambers'a are in the lowerhalf of the chamber 0-, the screw 0 is inserted until it jams the twosides of the bagftogether, the air-pressure is let off, the chamber 0 isthen opened, and the bag f is secured just above the part held by thescrew 0. bag f is then ready to be inserted into an outer cover.

It will be understood that one or more bags f, containing air-chambersunder pressure, may be employed to fill the interior of an outer cover.Fig. 5 shows one complete bag f and portions of two adjacent bagsmeeting at the points marked When one of the air-chambers (1 becomespunctured, if it is of the type shown in Fig. 1, the other air-chamberswill expand and fill up the gap. When they are of the type shown in Fig.2, the hemispherical ends will expand, and as the chambers arerestrained in diameter and are not a tight fit in the canvas bag f theywill soon slide along in said bag and equalize the pres sure therein.

Any of the usual forms of outer cover may be employed. I find that acover g, 113V? ing interlocking edges 9, as shown in Fig. 6, givessatisfactory results. The cover 9 is placed around a number of thebagsf, containing the air-chambers a under pressure, and the edges g areinterlocked. The complete tire may then be sprung onto a rim h, as theinterlocking edges g are somewhat elastic longitudinally.

1', having two endless wires i, is employed, I form the rim j as shownin section at Fig. 7. The main portion j of the rim is fitted with TheIf, however, a cover.

the spoke-nipples and has one side of the usual pattern to accommodatecovers 2', having endless wires 1'. The portion j has a recess j and arib 7' In conjunction with the main portion j I use a strip or strips jhaving a portion j to fit the recess j. In putting such a cover 2' upona rim one edge or endless wire is placed in position, the bags f,containing the air-chambers under pressure, are then placed under saidcover, and the other side of the cover is wrapped around the bags f. Theloose stripj is then forced into position by lateral pressure until theportion 9' jumps into the recess j. The said strip j would be made witha cutj to allow it to expand in order to get it into place, and theendsj would be provided with locking means, such as shown in Fig. 8, inwhich one side is provided with a hook j to fasten onto a stud j Such astrip 3' may be made in two or more parts, each being provided withsimilar locking means.

In some cases I may insert the air-chambers a inside an ordinaryair-tube k, fitted with a valve 7t, as shown in Fig. 9. In such a tire Imay use fewer canvas bagsfand perhaps only one of suficient length toencircle the rim. When some of the air-chambers in such a tire havebecome punctured, I can first repair the punctures in the air-tube k andthen inflate the same. The air-pressure in the air-tube will passthrough the canvas bag fand cause the air-chambers a to become smaller,if of the type shown in Fig. 1, and these latter will then more easilyspread them selves out around the tire and fill up any gaps caused bythe punctured ones.

The tire shown in Fig. 10 is formed with one long canvas bag f, formedinto the shape of a circle and containing sufiicient air-chambers tofill the same. The ends are then joined by a piece of canvas Z,solutioned to the same, and the whole is covered with india-rnbber m.

In Fig. 11 I have shown a tire having an outer cover, a number of canvasbags f filled with air-chambers a, and an inflatable airtube k, arrangedbetween the bags fand the rim h. If it should happen that severalairchambers a become punctured, and the pressure is thus reduced in theremaining ones, this deficiency of pressure may be counteracted byinflating the air-tube 70, which would also expand and fill up any gapsbetween the chambers until new air-chambers can be inserted.

It is proposed to make the canvas bag f of various lengths, so that ashort one may be purchased containing the air-chambers a under pressure,and in the case of tires of the type shown in Figs. 6' and 7, where theouter cover can be removed, the bagsf, already located therein, may bemoved by hand more closely together and a new canvas bag f of shortlength may be inserted to fill up the space more completely.

In some cases the hemispherical ends of the air-chambers are alsocovered with canvas, especially in the case of heavy tires suitable formotor-cars and the like.

iVhat I claim as my invention, and desire to secure by Letters Patent,is

l. A pneumatic tire containing a number of closed air-chambers made ofindia-rubber arranged inside a canvas bag, the requisite air-pressure inthe chambers being produced by external pressure prior to closing thebag.

2. A pneumatic tire containing a number of air-chambers made ofindia-rubber, with a restraining-cover, arranged inside a canvas bag,the requisite air-pressure beingproduced by external pressure prior toclosing the bag.

3. In a pneumatic tire, the combination of a number of air-chambers, arestraining-cover placed around the center of each to prevent themextending laterally, uncovered ends, a canvas bag in which suchair-chambers are placed, the requisite air-pressure being produced insaid chambers by external pressure prior to closing the bag, and anouter cover, substantially as set forth.

4:. A pneumatic tire containing a number of air-chambers which, afterbeing reduced in size by external pressure, are confined by means of acanvas bag, substantially as set forth.

5. In a pneumatic tire, the combination of an outer cover, a number ofair-chambers under pressure, a canvas bag containing such air-chamberswhich are reduced in size by ex ternal pressure prior to closing thebag, and means for closing the outer cover, substantially as set forth.

6. In a pneumatic tire, the combination of an outer cover having endlesswires, a number of air-chambers, a canvas bag containing suchair-chambers under pressure, which are reduced in size by externalpressure prior to closing the bag, a rim with a recess, and a loosestrip fitting said recess in the rim, substantially as set forth.

7. In a pneumatic tire, the combination of an outer cover, a number ofair-chambers, a canvas bag containing such air-chambers under pressure,and an inflatable tube in which the canvas bag is placed, substantiallyas set forth.

8. In a pneumatic tire, the combination of an outer cover, a number ofair-chambers, a canvas bag containing such air-chambers under pressure,and an inflatable tube arranged between such canvas bag and the rim,substantially as set forth.

9. In a pneumatic tire, the combination of a number of air-chambers a, arestrainingcover I) placed around the central part of each chamber toprevent lateral expansion and leaving the ends uncovered, a canvas bag fin which said chambers are confined and tightly com pressed endwise andan outer cover, substantially as described.

In testimony whereof I aflix my signature in presence of two witnesses.

F. MITCHELL.

Witnesses:

B. J. B. MILLS, WM. GIRLING.

